A foil gas dynamic pressure bearing

Abstract

The application relates to the technical field of gas dynamic pressure bearings, and provides an inserted sheet type foil gas dynamic pressure bearing which comprises a top foil, an inserted sheet, a bottom foil and a bearing sleeve; wherein a plurality of inserted sheets are circumferentially distributed and have a plurality of protruding pins on both sides; adjacent pins of adjacent inserted sheets are alternately distributed in the axial direction; the pins are inserted into groove holes of the arc-shaped bottom foil to form a support effect similar to a simply supported beam, and support the arc-shaped top foil; the pins of the inserted sheet are placed in grooves of the bearing sleeve after passing through the groove holes of the bottom foil, so that axial movement of the inserted sheet is avoided. The inserted sheet is used as a support structure, the problem that a support foil of a traditional gas bearing is plastically deformed after long-term work or under a large load is solved, the face contact friction between the inserted sheet and the top foil is used to provide high damping for the bearing, circumferentially distributed inserted sheets generate circumferentially uneven stiffness distribution of the bearing, local gas film wedges are beneficial to be formed, and the system stability and service life can be improved.

Description

Technical Field

[0001] This invention relates to the field of gas dynamic bearing technology, and specifically to a plate-type foil gas dynamic bearing. Background Technology

[0002] As energy and power equipment develops towards higher energy density, increasing rotational speed has become an important way to achieve this goal. Compared with traditional oil-lubricated bearing rotor systems, foil gas bearings, which use low-viscosity ambient gas as the lubricating medium and are in a completely suspended state, have advantages such as compact structure (oil-free lubrication), low friction, and high rotational speed (high energy density DN value). They are widely used in high-speed rotating mechanical equipment such as fuel cell air compressors, air circulators, micro gas turbines, and micro turbojet engines.

[0003] Common foil gas bearings consist of a top foil, elastic foils, and a bearing sleeve. The elastic foils have a corrugated structure, shaped by molding and subjected to high-temperature heat treatment to ensure axial uniformity. Under film pressure, the corrugated structure expands laterally and gradually returns to its original state after unloading. The contact friction with the top foil and bearing sleeve provides support stiffness and damping for the bearing. However, due to the continuous high-frequency vibration of the elastic foils by the high-speed rotor and the impact excitation during use, the corrugated structure may undergo plastic deformation after prolonged expansion and contraction of the spring foils. This leads to an increase in the film gap of the bearing. Furthermore, the small surface contact between the top foil and the elastic foil support fails to provide effective frictional damping for the bearing, making foil gas hydrodynamic bearings prone to subsynchronous vibration instability. Summary of the Invention

[0004] To address the aforementioned technical shortcomings, this application provides an insert-type foil gas hydrodynamic bearing. It employs circumferentially distributed inserts and a bottom foil to form a simply supported beam structure with supports at both ends. This allows for significant contact friction between the inserts and the top foil, and between the bottom foil and the bearing sleeve, greatly improving the bearing's resistance to impact loads and its durability. This solves the technical problems of low damping and plastic deformation in existing foil gas hydrodynamic bearings. The numerous technical effects of the preferred solutions among the many technical solutions provided by this invention are described below.

[0005] To achieve the above technical objectives, the present invention provides the following technical solution: a insert-type foil gas dynamic bearing, comprising a top foil, inserts, a bottom foil, and a bearing sleeve; wherein, multiple inserts distributed circumferentially have multiple protruding insert pins on both sides, and insert grooves are formed between adjacent insert pins; the insert pins and insert grooves are alternately distributed axially; one side of the insert pin is inserted into the slot of the bottom foil after passing through the insert groove of the adjacent insert, and extends continuously into the groove of the bearing sleeve, preventing axial movement of the insert; the insert pins on both sides support the insert, so that the insert forms a support effect similar to a simply supported beam; the insert supports the arc-shaped top foil; the top foil and the bottom foil are unclosed arcs, one end of the top foil and the bottom foil are free, and the other end is fixed; the two fixed ends contact and are fixed on the bearing sleeve; the directions from the free ends to the fixed ends of the two structures are the same or different.

[0006] The inserts are evenly distributed along the circumferential direction. On both sides of the inserts, several insert pins and insert grooves are distributed along the axial direction. The axial width of the insert pins is slightly smaller than the width of the insert grooves. The insert pins on one side of the same insert and the insert grooves on the other side are in the same axial position. There is a certain circumferential distance between adjacent inserts. The middle part of the inserts supports the top foil.

[0007] The bottom foil is arc-shaped, with one end fixed to the bearing sleeve. Several slots are distributed circumferentially and axially on the bottom foil. The positions of the slots are consistent with the design positions of the insert pins, and are used to support the inserts.

[0008] The bearing sleeve is used to support the bottom foil. The bearing sleeve has a plurality of grooves and ribs distributed axially. The width of the grooves is equivalent to the width of the insert pins. The axial degree of freedom of the insert pins inserted into the grooves is restricted by the ribs.

[0009] Optionally, the top foil and the bottom foil are designed and manufactured as a single unit, without affecting the installation and function of the insert.

[0010] Optionally, the insert can be a straight line or an arc shape. When the arc-shaped insert is installed with the bottom foil, the curvature is opposite to that of the insert, forming multiple spindle-shaped structures distributed circumferentially.

[0011] Optionally, the insert and the bottom foil are arranged in multiple layers radially in the bearing. The upper bottom foil supports the upper insert upwards and acts downwards on the insert. The upper insert supports the top foil upwards and acts downwards on the upper bottom foil. The circumferential dimension of the upper bottom foil is slightly smaller than that of the bottom foil, and the circumferential dimension of the upper insert is slightly smaller than that of the insert. The bottom foil, the upper bottom foil, and the top foil are designed and manufactured as a single unit.

[0012] Optionally, the axial dimension of the insert is smaller than the axial dimension of the bearing, and several small inserts are distributed axially.

[0013] Optionally, an even smaller insert is placed above the smaller inserts distributed circumferentially, the smaller insert having a shape similar to that of the smaller inserts, and the pins of the smaller insert being inserted into the slots of the smaller inserts.

[0014] Optionally, the bearing sleeve is axially distributed with several grooves and ribs, which are replaced by support foils. The support foils are flat foils that are cut and bent into shape. They are composed of longitudinal beams distributed along the axial direction and transverse beams distributed along the circumference. The distance between adjacent longitudinal beams is slightly larger than the width of the insert pin. The arrangement of the transverse beams should not affect the installation or movement of the insert pin. The end of the support foil is fixed to the bearing sleeve, and the longitudinal beams constrain the axial movement of the insert inserted between the two longitudinal beams.

[0015] The present invention, by employing the aforementioned technology, has the following positive effects compared to the prior art: The present invention provides an insert-type foil gas dynamic pressure bearing, which structurally includes a top foil, inserts, a bottom foil, and a bearing sleeve; wherein, the circumferentially distributed inserts have multiple protruding insert pins on both sides, and there are insert grooves between adjacent insert pins. The insert pins and insert grooves are alternately distributed axially. The insert pin on one side of the insert passes through the insert groove of the adjacent insert and is inserted into the slot of the bottom foil, and continues to extend into the groove of the bearing sleeve, thus preventing axial movement of the insert. The insert pins on both sides support the insert, so that the insert forms a support effect similar to a "simply supported beam", eliminating plastic deformation of the bearing support structure. The middle part of the insert supports the top foil. The radial distance between adjacent inserts is greater than the radial distance at the middle of the inserts. The top foil cannot be supported at the adjacent inserts, resulting in uneven circumferential stiffness of the bearing. Under the action of gas pressure, the top foil undergoes local deformation, forming multiple "wedge" or "preload" effects, which helps to reduce the continuity of the bearing gas film and improve the stability of the bearing. In addition, the inserts deform downward into an arc shape under pressure and fit with the top foil, increasing the frictional contact area. At the same time, the deformation of the inserts will drive the bottom foil to move relative to the bearing sleeve, which also generates a contact friction effect. Both types of friction provide effective damping effect for the bearing, which is beneficial to the stability of the system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 An exploded view of an insert-type foil gas dynamic bearing provided in an embodiment of the present invention.

[0018] Figure 2 This is a front view of an insert-type foil gas dynamic bearing provided in an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the insert plate of an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the bottom foil of an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of a bearing sleeve for an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0022] Figure 6 This is a schematic diagram of an integrated foil of a insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0023] Figure 7 An exploded view of an arc-shaped insert bearing for an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0024] Figure 8 is a front view of the arc-shaped insert and bottom foil structure of an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0025] Figure 9 is an exploded view of the multi-layer insert and bottom foil structure of an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0026] Figure 10 is a front view of the multi-layer insert and bottom foil structure of an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0027] Figure 11 This is a schematic diagram of the axial distribution of inserts in an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0028] Figure 12 is a schematic diagram of the axial and circumferential distribution of the inserts in an insert-type foil gas dynamic bearing provided by an embodiment of the present invention.

[0029] Figure 13 is a schematic diagram of the axial and circumferential distribution of the multi-layer inserts of a insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0030] Figure 14 An exploded view of an insert-type foil gas dynamic bearing and a supporting foil provided in an embodiment of the present invention.

[0031] Figure 15 is an isometric view of the support foil and insert structure of an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0032] Figure 16 This is a schematic diagram of the support foil of an insert-type foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0033] The labels for the various figures in the diagram are as follows: 1-Top foil, 2-Insertion piece, 3-Bottom foil, 4-Bearing sleeve, 5-Integrated foil, 6-Upper insert piece, 7-Upper bottom foil, 8-Small-sized insert piece, 9-Even smaller-sized insert piece, 10-Support foil, 11-Arc-shaped insert piece, 21-Insertion piece pin, 22-Insertion piece groove, 31-Slot, 32-Second slot, 41-Rib plate, 42-Groove, 101-Longitudinal beam, 102-Crossbeam. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0035] In the description of this invention, it should be noted that, unless otherwise stated, "several", "multiple", and "multi-layer" mean two or more; the terms "upper", "lower", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0036] In the description of this invention, it should be noted that, unless otherwise stated, the terms "preload" and "wedge" should be interpreted broadly, that is, the air film thickness is not uniform in the radial direction of the bearing. For example, the bearing structure is preloaded during installation, or the preload formed during the bearing operation process has the same effect as the preload. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0037] The foil gas bearing provided in the embodiments of this application will now be described.

[0038] like Figures 1 to 5As shown, the insert-type foil gas dynamic bearing includes: a top foil (1), inserts (2), a bottom foil (3), and a bearing sleeve (4); wherein, the bottom foil (3) contacts and supports the inserts (2) in the bearing sleeve (4), and the inserts (2) support the top foil (1). Several inserts (2) are distributed circumferentially in the bearing, and there are multiple protruding insert pins (21) on both sides of the inserts (2). There are insert grooves (22) between adjacent insert pins (21), and the insert pins (21) and insert grooves (22) are alternately distributed in the axial direction of the inserts (2). One side of the insert pin (21) passes through the insert groove (22) of the adjacent insert (2) and is inserted into the slot (31) of the bottom foil (3), and continues to extend into the groove (42) of the bearing sleeve (4). The rib (41) of the bearing sleeve (4) restricts the axial movement of the insert (2). The insert (2) supported by the insert pins (21) on both sides makes the insert (2) form a support effect similar to a simply supported beam.

[0039] As a specific implementation plan, such as Figure 1-3 As shown, the inserts (2) are evenly distributed along the circumference of the bearing. Several insert pins (21) and insert grooves (22) are distributed along the axial direction on both sides of the inserts (2). The axial width of the insert pins (21) is slightly smaller than the width of the insert grooves (22). The insert pins (21) on one side of the same insert (2) and the insert grooves (22) on the other side are in the same axial position. There is a certain circumferential distance between adjacent inserts (2). The inserts (2) support the top foil (1).

[0040] As shown in Figure 4, the bottom foil (3) is an open arc shape, with one end fixed on the bearing sleeve and the other end free. Several slots (31) are distributed in the circumferential and axial directions of the bottom foil (3). The position of the slots (31) is consistent with the design position of the insert pin (21) and supports the insert (2).

[0041] like Figure 5 As shown, the bearing sleeve (4) is a closed ring. The bearing sleeve (4) has several grooves (42) and ribs (41) distributed axially. The width of the groove (42) is comparable to the width of the insert pin (21). The axial degree of freedom of the insert pin (21) inserted into the groove (42) is restricted by the ribs (41). The ribs (41) have the same radius and are used to support the bottom foil (3).

[0042] like Figure 1-2 As shown, the fixed ends of the top foil (1) and the bottom foil (3) are fixed on the bearing sleeve (4). The direction from the fixed end of the top foil (1) to the free end is the same as or different from the direction from the fixed end of the bottom foil (3) to the free end.

[0043] As shown in Figures 3 and 4, as an optional implementation, the adjacent insert pins (21) of the circumferentially arranged inserts (2) are inserted into the slots (31) of the bottom foil (3) after passing through the insert grooves (22) of the adjacent inserts (2). The adjacent insert pins (21) may or may not contact the insert grooves (22). When they contact, the slots (31) of the bottom foil (3) where the adjacent insert pins (21) are placed are not in the same circumferential position; when they do not contact, to avoid the bottom foil (3) from having long slots (31) that reduce the support stiffness, the slots (31) for the adjacent insert pins (21) and the second slot (32) are not in the same axial position.

[0044] like Figure 1 and Figure 5 As shown, as an optional implementation, the insert pin (21) placed in the groove (42) does not contact the bottom of the bearing sleeve (4); when the length of the insert pin (21) is large, the bottom foil (3) will be separated from the support of the bearing sleeve (4), so that the stiffness and damping of the bearing foil structure are provided by the contact part between the insert pin (21) and the bearing sleeve (4) under small loads, and under large loads, the insert pin (21) deforms and slides, the bottom foil (3) contacts the bearing sleeve (4), and the middle part of the insert (2) provides support stiffness and damping.

[0045] like Figure 6 As shown, as an optional implementation, the top foil (1) and the bottom foil (3) are designed and manufactured as a single unit, which does not affect the installation and function of the insert (2).

[0046] As shown in Figures 7 and 8, as an optional implementation, the insert (2) is a straight line or an arc shape; the arc insert (11) replaces the insert (2) and forms a "spindle" structure with the bottom foil. The arc insert (11) under pressure and the bottom foil (3) elongate and deform simultaneously, providing support stiffness and friction damping.

[0047] As shown in Figures 9 and 10, as an optional implementation, multiple layers are placed in the bearings of the insert (2) and the bottom foil (3). The upper bottom foil (7) supports the upper insert (6) upwards and acts downwards on the insert (2). The upper insert (6) supports the top foil (1) upwards and acts downwards on the upper bottom foil (7). The circumferential dimension of the upper bottom foil (7) is slightly smaller than that of the bottom foil (3), and the circumferential dimension of the upper insert (6) is slightly smaller than that of the insert (2). The bottom foil (3), the upper bottom foil (7), and the top foil (1) are designed and manufactured as an integrated foil sheet (5).

[0048] like Figure 11 As shown, as an optional implementation, the axial dimension of the insert (2) is smaller than the axial dimension of the bearing, and several small inserts (8) are distributed axially.

[0049] like Figure 12 As shown, as an optional implementation, a smaller insert (9) is placed above the smaller insert (8) distributed circumferentially. The shape of the smaller insert (9) is similar to that of the smaller insert (8). Slots are distributed axially on the smaller insert (8). The pins of the smaller insert (9) are inserted into the slots of the smaller insert (8). The radial dimension of the smaller insert (9) should be less than or equal to the radial dimension of the middle position of the smaller insert (8).

[0050] like Figure 13 to Figure 16 As shown, as an optional implementation, the bearing sleeve (4) has a plurality of grooves (42) and ribs (41) distributed axially, which are replaced by support foils (10). The support foils (10) are flat foils that are cut and bent into shape, and are composed of longitudinal beams (101) distributed axially and transverse beams (102) distributed circumferentially. The distance between adjacent longitudinal beams (101) is slightly larger than the width of the insert pin (21). The arrangement of the transverse beams (102) cannot affect the installation or movement of the insert pin (21). The end of the support foils (10) is fixed on the bearing sleeve, and the longitudinal beams (101) constrain the axial movement of the insert (2) inserted between the two longitudinal beams (101).

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, alterations, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A plate-type foil gas dynamic bearing, characterized in that, include: The components are: a top foil (1), a insert (2), a bottom foil (3), and a bearing sleeve (4); wherein, the multiple inserts (2) distributed circumferentially have multiple protruding insert pins (21) on both sides, and there are insert grooves (22) between adjacent insert pins (21). The insert pins (21) and the insert grooves (22) are alternately distributed axially. The insert pin (21) on one side of the insert (2) is inserted into the slot (31) of the bottom foil (3) after passing through the insert groove (22) of the adjacent insert (2), and continues to extend into the groove (42) of the bearing sleeve (4) to prevent the insert (2) from moving axially. The inserts (2) supported by the insert pins (21) on both sides form a support effect similar to a simply supported beam. The middle part of the insert (2) supports the arc-shaped top foil (1). The top foil (1) and the bottom foil (3) are fixed on the bearing sleeve (4).

2. The insert-type foil gas dynamic bearing according to claim 1, characterized in that, The inserts (2) are evenly distributed along the circumferential direction. On both sides of the inserts (2), a number of insert pins (21) and insert grooves (22) are distributed along the axial direction. The axial width of the insert pins (21) is slightly smaller than the width of the insert grooves (22). The insert pins (21) on one side of the same insert (2) and the insert grooves (22) on the other side are in the same axial position. There is a certain circumferential distance between adjacent inserts (2). The inserts (2) support the top foil (1).

3. The insert-type foil gas dynamic bearing according to claim 1, characterized in that, The bottom foil (3) is arc-shaped and is fixed on the bearing sleeve. Several slots (31) are distributed circumferentially and axially on the bottom foil (3). The position of the slots (31) is consistent with the design position of the insert pin (21) and supports the insert (2).

4. The insert-type foil gas dynamic bearing according to claim 1, characterized in that, The bearing sleeve (4) is used to support the bottom foil (3). The bearing sleeve (4) has a plurality of grooves (42) and ribs (41) distributed axially. The width of the groove (42) is equivalent to the width of the insert pin (21). The axial degree of freedom of the insert pin (21) inserted into the groove (42) is restricted by the ribs (41).

5. The insert-type foil gas dynamic bearing according to claim 1 or claim 3, characterized in that, The top foil (1) and the bottom foil (3) are designed and manufactured as a single unit, which does not affect the installation and function of the insert (2).

6. The insert-type foil gas dynamic bearing according to claim 1 or claim 3, characterized in that, The insert (2) is a straight line or an arc shape; the curvature of the arc insert is opposite to that of the bottom foil, forming multiple spindle-shaped structures distributed circumferentially.

7. The insert-type foil gas dynamic bearing according to claim 1, characterized in that, The insert (2) and the bottom foil (3) are placed in multiple layers in the radial direction of the bearing. The upper bottom foil (7) supports the upper insert (6) upward and acts downward on the insert (2). The upper insert (6) supports the top foil (1) upward and acts downward on the upper bottom foil (7). The circumferential dimension of the upper bottom foil (7) is slightly smaller than that of the bottom foil (3). The circumferential dimension of the upper insert (6) is slightly smaller than that of the insert (2). The bottom foil (3), the upper bottom foil (7), and the top foil (1) are designed and manufactured as a single unit.

8. The insert-type foil gas dynamic bearing according to claim 1 or claim 2, characterized in that, The axial dimension of the insert (2) is smaller than the axial dimension of the bearing, and several small inserts (8) are distributed axially. A smaller insert (9) is placed on top of the small inserts (8) distributed circumferentially. The shape of the smaller insert (9) is similar to that of the small insert (8), and the pins of the smaller insert (9) are inserted into the slots of the small inserts (8).

9. The insert-type foil gas dynamic bearing according to claim 4, characterized in that, The bearing sleeve (4) has a plurality of grooves (42) axially distributed and the ribs (41) are replaced by support foils (10). The support foils (10) are flat foils that are cut and bent into shape. They are composed of longitudinal beams (101) distributed axially and transverse beams (102) distributed circumferentially. The distance between adjacent longitudinal beams (101) is slightly greater than the width of the insert pin (21). The arrangement of the transverse beams (102) cannot affect the installation or movement of the insert pin (21). The end of the support foils (10) is fixed on the bearing sleeve. The longitudinal beams (101) constrain the axial movement of the insert (2) inserted between the two longitudinal beams (101).

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